diff --git a/day4.chpl b/day4.chpl
new file mode 100644
index 0000000..fbeb58d
--- /dev/null
+++ b/day4.chpl
@@ -0,0 +1,14 @@
+use IO;
+
+iter pairs() {
+  var low1, low2, high1, high2 : int;
+  while readf("%i-%i,%i-%i", low1, high1, low2, high2) do
+    yield (low1..high1, low2..high2);
+}
+
+proc anyContains((r1, r2): 2*range) { return r1.contains(r2) || r2.contains(r1); }
+proc overlap((r1, r2): 2*range) { return !r1[r2].isEmpty(); }
+
+var thePairs = pairs();
+writeln(+ reduce anyContains(thePairs));
+writeln(+ reduce overlap(thePairs));
diff --git a/day4.cr b/day4.cr
new file mode 100644
index 0000000..ddc71b6
--- /dev/null
+++ b/day4.cr
@@ -0,0 +1,38 @@
+require "advent"
+
+struct Range(B, E)
+  def contains?(other)
+    other.begin >= self.begin && other.end <= self.end
+  end
+
+  def overlaps?(other)
+    these = self.to_a
+    others = other.to_a
+    these.any? { |i| others.includes? i }
+  end
+end
+
+INPUT = input(2022, 4).lines.map do |line|
+  first, second = line.split(",").map do |str|
+    left, right = str.split("-").map &.to_i64
+    left..right
+  end
+  {first, second}
+end
+
+def part1(input)
+  input.count do |pair|
+    l, r = pair
+    l.contains?(r) || r.contains?(l)
+  end
+end
+
+def part2(input)
+  input.count do |pair|
+    l, r = pair
+    l.overlaps?(r)
+  end
+end
+
+puts part1(INPUT.clone)
+puts part2(INPUT.clone)